The primary source of greenhouse gases is the burning of fossil fuels (coal, oil, and natural gas) for energy production, transportation, and industry.
They are called greenhouse gases because they trap heat in the Earth's atmosphere, similar to how a greenhouse traps heat, leading to global warming.
The main greenhouse gases are Carbon Dioxide (CO₂), Methane (CH₄), Nitrous Oxide (N₂O), Hydrofluorocarbons (HFCs), Perfluorocarbons (PFCs), Sulfur Hexafluoride (SF₆), and Nitrogen Trifluoride (NF₃).
Greenhouse gas (GHG) emissions are one of the most critical environmental concerns and must be factored into decision-making processes for any industrial project. A project’s Environmental Impact Assessment (EIA) should prioritize significant impacts, and GHG emissions must be assessed in proportion to avoid unnecessary burdens on developers and regulators.
A 'good practice' approach ensures that GHG emissions are always considered and reported, with varying levels of detail based on the project's scope. This practice helps to develop a deep understanding of how GHG emissions should be effectively assessed.
During project execution, an emissions and discharges report is prepared to estimate cumulative GHG emissions over the project's operational life. This report may also include simulations of alternative scenarios, aiding in selecting Best Available Techniques (BAT) to minimize environmental impact.
BAT focuses on reducing environmental impacts to "As Low As Reasonably Practicable" (ALARP) by implementing state-of-the-art technologies where technically and economically feasible. BAT assessments support design choices that optimize environmental performance while balancing technical and financial constraints.
The first step includes a screening of available alternatives. During a workshop, or as a desktop exercise, alternatives are listed and a high-level evaluation of the implications in terms of environmental performance, technical applicability, and economic availability is carried out. This evaluation may be based on Client’s input, publicly available information, vendor data, or experience from previous projects. The aim of the screening step is to establish a short list of alternatives that may be studied and compared in more detail. Only those alternatives that are deemed to perform best from the environmental perspective, while being technically and economically feasible are selected.
The next step is an in-depth evaluation of each alternative. It consists of an estimation of the resource use, emissions and discharges, including waste generation and reuse/recycling potential for each alternative. At this stage, it is important to clearly define the boundaries of the system since this will form the basis for the comparison of alternatives on the environmental basis. It is equally important to select the right parameters for which the environmental performance is to be measured against.
The alternatives are then ranked based on their environmental performance. In some cases, it is necessary to establish a trade-off between different environmental performance parameters, for example between oil in water content and energy use for a produced water treatment system; a treatment system may be very efficient in removing oil particles from the water, but the process might be very energy intensive.
Once alternatives are ranked according to the environmental performance, the technical implications of each alternative are investigated. Typical technical constraints include space and weight, the techniques availability and maintainability, consequences on the safety level (e.g. due to use of gas or pressurized steam), and the technical compatibility with the overall design. Alternatives may then be ranked on the technical criteria, or simply being defined as “technically feasible” or “not technically feasible”.
The next activity in step two is to investigate the economic availability for each alternative. This should involve an evaluation of the capital expenditure (CAPEX) and also operational expenditure (OPEX). CAPEX may be established based on vendor quotes or data from previous projects. OPEX should include maintenance costs, potential repair or replacement costs, but also costs linked to emissions. Similar to the technical criteria, alternatives are then ranked according to their costs.
Finally, in step 3, the alternatives are compared, and the best available technique is established. The aim is to determine the best compromise between environmental performance, technical feasibility and economically viable where the highest weight is given to the environmental performance.
This structured approach ensures that GHG emissions are minimized and managed effectively throughout the project lifecycle. By utilizing BAT and focusing on proportionate assessments, the project achieves compliance with environmental standards while maintaining technical and economic feasibility. This process helps drive innovation and sustainable practices, ensuring that environmental impacts are mitigated for ALARP.
